This invention relates to a tool combining rod, particularly to one able to fix the engaging head member of quickly and firmly, with the engaging head member possible to be lengthened and applicable to an automatic, screwdriver.
Conventional tool combining rods are almost the same in structure. One conventional tool combining rod shown in FIGS. 1, 2 and 3 includes a rod member 1 and an engaging head member 2. The rod member 1 is bored at the front end with a combining hollow 10 have the same shape as that of the rod portion 20 of the engaging head member 2 so as to let them combined together closely. The combining hollow 10 is bored with one or two bead holes 12 in its wall 11 for receiving a bead 13, which is pressed by a sleeve 14, as shown in FIGS. 1 and 2. Or the combining hollow 10 may have its wall 11 bored with a C-shaped groove 12A for a C-shaped clasp 13A to be fitted therein, as shown in FIG. 3. Further, between the engage hole 12 and the engage bead 13 or between the C-shaped groove 12A and the C-shaped clasp 13A there must be a space and a little elasticity for the engage bead 13 and the C-shaped clasp 13A to move around in order to permit the engaging head member 2 to be pulled out for replacing and inserted in place with easiness.
A fourth conventional tool combining rod, as shown in FIG. 4, includes a rod member 1 provided with a combining hollow 10 having a hole 15 in the rear side, and a C-shaped groove 12A in its wall for receiving a C-shaped clasp 16. Thus, in case the engaging head member 2 has to be pulled out or replaced, an auxiliary tool 3 has to be inserted in the hole 15 and pushed the bottom of the engaging head member 2 outward so as to take out or replace the engaging head member 2.
However, each of the four conventional tool combining rods described above needs to be provided with a bead hole 13 or an annular groove 21 in the rod portion 20 of the engaging head member 2 not only to let the engaging head member 2 fixed in position by the bead(s) 13 or the C-shaped clasps 13A, 16, but also enable the bead(s) 13 or the C-shaped clasp 13A, 16 to move respectively in the bead hole 12 or in the C-shaped groove 12A, thus letting the engaging head member 2 and the combining hollow 10 combined together or disengaged from each other smoothly and easily.
In view of the above-mentioned condition, the thickness L of the hollow wall 11 has to be set within a proper range. The conventional tool combining rods shown in FIGS. 1, 2 and 3 all have too large an outer diameter (over 7 mm) so they are not applicable to an automatic screwdriver 4 fitted with a screw band, but only available for a common tool having a comparatively short combining rod. The fourth conventional tool combining rod shown in FIG. 4 has the outer diameter of its rod member 1 diminished to conform to the foresaid automatic screwdriver. Under this condition, after the engaging head member 2 is combined with the combining hollow 10 of the rod member 1, the engaging head member 2 is closely stuck by the C-shaped clasp 16 in such a condition that it can hardly be pulled out by hand, and so the rod member 1 has to be bored with the side hole 15 for an auxiliary tool 3 to insert therein and prop out the engaging head member 2 by means of an auxiliary tool. However, the side hole 15 bored in the wall of the rod member 1 will reduce the strength of the rod member 1, possible to render the tool combining rod 1 twisted, deformed and broken off at the location of the side hole 15 in the event of the twisting force of combination being too large.
Still the fifth conventional tool combining rod shown in FIG. 5, includes a rod portion 1 having a combining hollow 10 in the front end. The combining hollow 10 has its annular wall 11 bored with a bead hole 12 for receiving a bead 13. A contractible spring 14 is provided on the outer side of the hollow wall 11 of the combining hollow 10, having one end pushing against the annular surface 111 of the hollow wall 11 and the other end pushing against the inner annular surface 140 of a slide sleeve 14A, and positioned between the slide sleeve 14A and the hollow wall 11 of the combining hollow 10. Besides, the combining hollow 10 has its wall provided annularly with a C-shaped clasp 112 to prevent the slide sleeve 14A from slipping off. The slide sleeve 14A has its front end formed with an inner sloping annular edge 141 so as to let the combination of the bead(s) 13 with the engaging head member 2 able to be loosened for facilitating removing or replacing the engaging head member 2.
As described above, the fifth conventional tool combining rod shown in FIG. 5 has a slide sleeve 14A provided on the rod member 1 for replacing the engaging head member 2 easily, but the outer diameter d1 of the slide sleeve 14A is much larger than the outer diameter d2 of the rod member 1. As a result, such a tool combining rod provided with two combining components is not applicable to an automatic screwdriver 4. In operating, the automatic screwdriver 4 used at the present usually has a screw screwed out and then screwed into an objective, and the automatic screwdriver unit 42 may recover its original position by the recovering resilience of the contractible spring 14. At this time, the outer annular wall of the tool combining rod is positioned in a screw bend hole 401 and wrapped by the annular wall of a screw hole 402. If the tool combining rod is too large, it is hard for the automatic screwdriver tool unit 42 to recover its original position, failing to operate smoothly.
Therefore, the tool combining rod employed today has a small outer diameter and is made integral as one 1C, as shown in FIGS. 6, 7 and 8, but this integrally made tool combining rod 1C may become unusable and has to be replaced or cast away in case the engage portion 22 of its engaging head member 2 is worn off, increasing cost in using.
This invention is devised to offer a tool combining rod having a small outer diameter (less than 7 mm) and applicable to an automatic screwdriver, able to be operated smoothly and lower cost in manufacturing.
The present invention has the following features.
1. The tool combining rod consists of a rod member having one end formed with a non-round and equiangular portion to be combined with a drive tool for transmitting power, and the other end provided with a combining hollow and having an outer diameter smaller than or equal to the largest outer diameter of foresaid non-round surface, with the combining hollow provided with an inner annular surface for facilitating receiving an engage member.
2. The engage member is bored with a central hole for receiving the rod portion of the engaging head member, and provided with an elastic annular surface for combining with the inner annular surface of the combining hollow of the rod member and firmly holding the engaging head member to prevent it from slipping off.
3. The tool combining rod is composed of a rod member, an engaging head member and an engage member, therefore in case the engaging head member is worn off due to driving screws, it needs only to replace the engaging head member, reducing expenditure of a user.